Fixed #8172 -- Improved a whole bunch of contrib templates (admin, databrowse,...

Fixed #8172 -- Improved a whole bunch of contrib templates (admin, databrowse, admindocs, etc.) to remove unnecessary 'escape' filters, given autoescaping. Also removed unnecessary {% if %} tags and shortened some {% if %}/{% else %} tags to use {% firstof %}. Thanks for the patch, benspaulding

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8984 bcc190cf-cafb-0310-a4f2-bffc1f526a37